Why You Don’t Know Your Own Mind

It is often said that we can never truly know the minds of others, because we can’t “get inside their heads.” Our ability to know our own minds, though, is rarely called into question. It is assumed that your experience of your own consciousness clinches the assertion that you “know your own mind” in a way that no one else can. This is a mistake.

Ever since Plato, philosophers have, without much argument, shared common sense’s confidence about the nature of its own thoughts. They have argued that we can secure certainty about at least some very important conclusions, not through empirical inquiry, but by introspection: the existence, immateriality (and maybe immortality) of the soul, the awareness of our own free will, meaning and moral value. In a Stone column Gary Gutting explained how this tradition continues to manifest itself in contemporary philosophy as the search for “a ‘transcendental’ or ‘absolute’ consciousness that provides the fuller significance of our ordinary experiences.” Thomas Nagel has invoked the same source to trump science in this publication as well.

Introspection, “the mind’s eye,” assures us with the greatest confidence that it is the best, in some cases the only authority on how the mind works, because we all think it has direct, first person access to itself. We’re all very confident that we just know what’s going on in our own minds, from the inside, so to speak.

Yet research in cognitive and behavioral sciences increasingly undermines that confidence. It seems hardly a week goes by without another article in the media reporting counterintuitive laboratory findings by empirical psychologists studying cognition, emotion and sensation. What makes many of these results remarkable is their consistent violation of expectations, assumptions and prejudices forced on us by our own conscious awareness.

In fact, controlled experiments in cognitive science, neuroimaging and social psychology have repeatedly shown how wrong we can be about our real motivations, the justification of firmly held beliefs and the accuracy of our sensory equipment. This trend began even before the work of psychologists such as Benjamin Libet, who showed that the conscious feeling of willing an act actually occurs after the brain process that brings about the act — a result replicated and refined hundreds of times since his original discovery in the 1980s.

Around the same time, a physician working in Britain, Lawrence Weiskrantz, discovered “blindsight” — the ability, first of blind monkeys, and then of some blind people, to pick out objects by their color without the conscious sensation of color. The inescapable conclusion that behavior can be guided by visual information even when we cannot be aware of having it is just one striking example of how the mind is fooled and the ways it fools itself.

Meanwhile, philosophy has largely persisted in its centuries-long Cartesianism — following Descartes’ insistence in his “Meditations” (1641) that our knowledge of our own minds’ nature is more reliable than any other belief. Galen Strawson recently illustrated this centuries-old conviction in a recent essay in The Stone: “We know what conscious experience is because the having is the knowing: Having conscious experience is knowing what it is.” He writes “It is in fact the only thing in the universe whose ultimate intrinsic nature we can claim to know.”

Despite these assurances from philosophy, empirical science has continued to build up an impressive body of evidence showing that introspection and consciousness are not reliable bases for self-knowledge. As sources of knowledge even about themselves, let alone anything else human, both are frequently and profoundly mistaken.

To see the mistake we need to recognize another mistake Descartes made: his denial that other animals have any mental lives at all. Careful field observation by primatologists beginning with Jane Goodall revealed that apes have well developed “theories of mind.” They engage in “mind reading” to make (sometimes good) guesses about the future behavior of others. Mind reading is psychologists’ shorthand for treating other animals as having something like desires and beliefs that work together to produce choices in behavior.

After a certain point in the evolutionary past, organisms began needing to predict whether others posed threats in order to protect themselves, and later needed to coordinate to attain outcomes not achievable alone. This environment strongly selected for mind reading. Had variation in cognitive abilities not hit on this adaptation, puny creatures like us would never have survived in the face of savanna megafauna.

Mind reading, even in our own hands, is a very imperfect tool: We have to go on others’ behavior (including verbal behavior). We can’t really tell with much precision exactly what others believe or want, because we can’t get inside their heads. So our predictions are often pretty vague and frequently false. Like other Darwinian adaptations, mind reading is an imperfect, “quick and dirty” solution to a “design problem.” It was just good enough that, equipped with this theory of mind, we managed to gradually climb to the top of the food chain. We were able to do so in large part because once mind reading was in place human language, which requires it, became possible.

FMRI research, the study of autism, and experiments on infant “false-belief” detection have shown that mind reading is a relatively well-localized module in the human brain, innate in structure, subject to breakdown — often genetically caused, and identifiable in infant/toddler development.

Most important, there is compelling evidence that our own self-awareness is actually just this same mind reading ability, turned around and employed on our own mind, with all the fallibility, speculation, and lack of direct evidence that bedevils mind reading as a tool for guessing at the thought and behavior of others. When, as David Hume said, we look into ourselves, all we ever see are images, all we ever hear is silent speech-sounds. These sensations (along with emotions) are the only contents of consciousness, the only things introspection can use to figure out what we are thinking. The resources of introspection are exactly the same as the resources our minds work with to explain and predict the actions of others: sensory data provided by sight, hearing, smell, touch (and sometimes taste, too).

Of course we have a lot more sensory data — images and silent speech instead of visual experience and heard speech — to go on in trying to figure out our own desires and beliefs than what other people’s behavior reveals about what is going on in their minds. That’s part of what makes for the illusion that we know our own minds so much better. But the difference is only the amount of data, not its quality or source. We never have direct access to our thoughts. As Peter Carruthers first argued, self-consciousness is just mind reading turned inward.

How do we know this? Well, Hume would have answered that introspection tells us so. But that won’t wash for experimental scientists. They demand evidence. Some of it comes from the fMRI work that established the existence of a distinct mind-reading module, more from autistic children, whose deficits in explaining and predicting the behavior of others come together with limitations on self-awareness and self-reporting of their own motivations. Patients suffering from schizophrenia manifest deficiencies in both other-mind reading and self-mind reading. If these two capacities were distinct one would expect at least some autistic children and schizophrenics to manifest one of these capacities without the other.

That we read our own minds the same way we read other minds is evident in what cognitive science tells us about consciousness and working memory — the dual imagistic and silent-speech process that we employ to calculate, decide, choose among options “immediately before the mind.” The most widely accepted psychologist’s theory of consciousness identifies it as a mode of “global broadcast” solely from sensory modalities to “executive”— deciding, and “affective”— feeling systems that act on this sensory input. Self-consciousness has nothing else to work with but the same sensory data we use to figure out what other people are doing and are going to do.

The upshot of all these discoveries is deeply significant, not just for philosophy, but for us as human beings: There is no first-person point of view.

Our access to our own thoughts is just as indirect and fallible as our access to the thoughts of other people. We have no privileged access to our own minds. If our thoughts give the real meaning of our actions, our words, our lives, then we can’t ever be sure what we say or do, or for that matter, what we think or why we think it.

Philosophers’ claims that by reflecting on itself thought reliably reveals our nature, grounds knowledge, gives us free will, endows our behavior with moral value, are all challenged. And the threat doesn’t stem from some tendentious scientistic worldview. It emerges from the detailed understanding of the mind that cognitive science and neuroscience are providing.

Alex Rosenberg is co-director of the Center for Social and Philosophical Implications of Neuroscience in the Duke Initiative for Science and Society. His second novel, “Autumn in Oxford” will appear in August.